Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the behavioral burden and does so well: it discloses that the computation is deterministic and LLM-free, that Moon nakshatra/rashi are derived through the same chart engine as get_chart_facts, and that the output is auditable with per-koota scores, maximums, and reasons. It could add more detail about result shape or ordering, but the key behaviors are covered.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Four sentences with no filler: purpose and field list are front-loaded, the computation rule is stated directly, the deterministic/no-LLM note is a single fragment, and the output/auditability promise earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The input schema is exhaustive and the description covers the output shape at the per-koota level (score, maximum, plain-language reason), which is important because there is no output schema. A small gap is that the top-level response shape and potential order sensitivity between person_a and person_b are not addressed, but the essential calling information is present.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already provides 100% coverage of dob/tob/lat/lng/tz for person_a and person_b, so the baseline is 3. The description adds value beyond the schema by clarifying that these parameters are raw birth data and that nakshatra/rashi must not be passed, which prevents a common misuse.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific domain and resource: Vedic compatibility (Guna Milan/Ashtakoota) between two people, and quantifies it as 36 points across eight named kootas. This clearly identifies the tool's purpose and distinguishes it from sibling tools like get_chart_facts (single chart), get_panchang (calendar), and ask_jyotish (query).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It conveys the intended use case — pairwise compatibility via birth charts — and gives an explicit rule: pass raw birth data and do not pass nakshatra/rashi because they are computed internally. It does not explicitly contrast against sibling tools or state when not to use it, but the context is clear enough for selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.